In case of +cheap +flight, your ads will show with close variants of cheap and flight in any order.

In case of +cheap +international +flight, your ads will show with close variants of cheap international flight in any order.

The real key is that only one keyword per account is allowed to trigger an ad. So my advice would be to look at the search terms if you are trying to use both the keywords and then try to use different match types so that one keyword doesn't eat away traffic of other keyword.

Re: Query regarding BMM match type

I´d also use a higher bid for +cheap +international +flights, not only because it is more narrow and targeted (thus should have a better conversion rate), but also to make it a little more probable that it will trigger the ad when someone searches for "tickets for cheap international flights" (for example).

Re: Query regarding BMM match type

They do not compete in the way keywords in an auction does, but if the keyword with the highest AdRank also is the keyword with the highest bid that will probably cost you more per click than if the keyword with the lower bid wins the auction